構造用ムライトのき裂治癒能力と治癒材の高温強度特性に及ぼすY_2O_3の効果

概要

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Crack healing behavior and high temperature strength of Mullite/SiC composite ceramics have been investigated systematically, as a function of Y_2O_3 added(0〜2.5wt%). The specimen was sintered by hot-pressing at 1650℃. Semi-elliptical surface crack of 100μm in diameter was made on the specimen. Cracked specimen was heat-treated at 1100℃ for 3hours, or at 1300℃ for Ihour in an air. Bending strength was measured by a 3-point bending test system. The bending strengths of smooth specimens were reduced to 40%-25% by the above cracking. For the case of mullite/SiC/Y_2O_3, the bending strength of heat-treated specimens with crack recovered completely up to that of smooth specimens. On the contrary, for the case of mullite /Y_2O_3(Y_2O_3=0〜2.5wt%), the bending strength was recovered incompletely. This strength recovery of both materials was caused by crack-healing. This crack-healing ability was increased considerably by adding SiC particle to mullite. By adding 0.5〜2.0wt% Y_2O_3 to mullite/SiC composite ceramics, heat-resisting limit temperature of crack-healed sample was increased from about 1100℃ to 1200℃.
社団法人日本材料学会の論文
2002-04-15